DC power supply system

Abstract

A DC power supply system includes: a natural energy power generator connected to a DC bus through a first DC-DC converter; a load device connected to the DC bus through a second DC-DC converter; a storage battery connected to the DC bus through a third DC-DC converter and configured to be charged with a generated power when the generated power is larger than a load power and to be discharged to supply power to the load device when the generated power is smaller than the load power; and a power management apparatus that manages operations of the first to third DC-DC converters based on current power generation amount and load power amount, prediction values for future power generation amount and load power amount, a remaining capacity of the storage battery, preset target values for respective blackout rate, battery lifetime, and power suppression rate, and the priorities among the target values.

The invention claimed is: 
     
       1. A DC power supply system comprising:
 a DC bus serving as a bus bar for DC power supply; 
 first to third DC-DC converters connected to the DC bus; 
 a natural energy power generator that is connected to the DC bus through the first DC-DC converter and supplies generated power to the DC bus; 
 a load device that is connected to the DC bus through the second DC-DC converter and receives supply of a load power from the DC bus; 
 a storage battery that is connected to the DC bus through the third DC-DC converter and configured to be charged with the generated power when the generated power is larger than the load power and to be discharged to supply power to the load device when the generated power is smaller than the load power; and 
 a power management apparatus that manages operations of the first to third DC-DC converters based on current power generation amount and load power amount, prediction values for future power generation amount and load power amount, the remaining capacity of the storage battery, previously set target values for respective blackout rate, battery lifetime, and power suppression rate, and the priorities among the target values. 
 
     
     
       2. The DC power supply system according to  claim 1 , wherein
 the power management apparatus includes 
 a target value setting part for setting the target values for respective blackout rate, battery lifetime, and power suppression rate and 
 a priority setting part for setting the priorities among the target values for respective blackout rate, battery lifetime, and power suppression rate. 
 
     
     
       3. The DC power supply system according to  claim 2 , wherein
 the power management apparatus further includes 
 a weather data acquisition part that acquires weather forecast data, 
 a data storage that stores data of the power generation amount and load power amount, and 
 a power amount estimator that estimates a future power generation amount and a future load power amount based on the weather forecast data and the data of the power generation amount and load power amount stored in the data storage. 
 
     
     
       4. The DC power supply system according  claim 1 , wherein
 when the prediction value for the blackout rate exceeds the target value for the blackout rate, the power management apparatus controls the second DC-DC converter so as to suppress the load power amount. 
 
     
     
       5. The DC power supply system according to  claim 1 , wherein
 when the prediction value for the battery lifetime exceeds the target value for the battery lifetime, the power management apparatus controls the second DC-DC converter so as to suppress the load power amount and controls the first DC-DC converter so as to suppress the power generation amount. 
 
     
     
       6. The DC power supply system according to  claim 1 , wherein
 when the prediction value for the power suppression rate exceeds the target value for the power suppression rate, the power management apparatus controls the first DC-DC converter so as to suppress the power generation amount. 
 
     
     
       7. The DC power supply system according to  claim 1 , wherein
 the power management apparatus dynamically changes the priorities among the target values for respective blackout rate, battery lifetime, and power suppression rate. 
 
     
     
       8. The DC power supply system according to  claim 1  further comprising an administrator terminal configured to communicate with the power management apparatus, wherein
 the power management apparatus notifies the administrator terminal of recommended values for the target values for respective blackout rate, battery lifetime, and power suppression rate and those for the priorities. 
 
     
     
       9. The DC power supply system according to  claim 1 , wherein
 the power management apparatus automatically sets the recommended values for the target values for respective blackout rate, battery lifetime, and power suppression rate, and those for the priorities. 
 
     
     
       10. The DC power supply system according to  claim 1 , wherein
 the first DC-DC converter is a step-up converter that steps up a power from the natural energy power generator and supplies the resultant power to the DC bus, 
 the second DC-DC converter is a step-down converter that steps down a power on the DC bus and supplies the resultant power to the load device, and 
 the third DC-DC converter is a bidirectional DC-DC converter that steps down or up a power on the DC bus and supplies the resultant power to the storage battery, as well as steps up or down a power from the storage battery and supplies the resultant power to the DC bus.